Oracle Database Discussions

I am a beginner in oracle. I completed Admin1 cert & now preparing for OCP. While testing RMAN i created a database using DBCA for RMAN Catalog. First time i am trying and database created in noarchive log. Though i was not able to successfully backup & recover, i got clarity on the concepts. (I am learning on my own- so need a do a lot of research to clarify doubts).

Coming to the point. Since two database i can open two em consoles and do operations at same time. But in command mode when i try i am facing issues. At one point of time i am not able to fine which database is running and how to enable or disable the other.

I logged in and execute shutdown immediate. It shutdown one database. I switched the oracle_sid and tried to shutdown second, but it did not happen. Then i did it from EM.


Then i tried to restart the server.. I executed the following commands.

C:\Documents and Settings\MaverickBull>set oracle_sid=ora10g

C:\Documents and Settings\MaverickBull>sqlplus sys as sysdba/oracle123@ora10g

SQL*Plus: Release 10.2.0.1.0 - Production on Fri Nov 19 13:11:40 2010

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Enter password:
Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area 612368384 bytes
Fixed Size 1250428 bytes
Variable Size 205523844 bytes
Database Buffers 398458880 bytes
Redo Buffers 7135232 bytes
Database mounted.
Database opened.

SQL> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Pr
oduction
With the Partitioning, OLAP and Data Mining options

--- Oracle instance Ora10g started. Now i want to start the second one from cli*

C:\Documents and Settings\MaverickBull>sqlplus sys as sysdba/oracle123@ora10grc

SQL*Plus: Release 10.2.0.1.0 - Production on Fri Nov 19 13:13:26 2010

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Enter password:

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options

SQL> startup;
ORA-01081: cannot start already-running ORACLE - shut it down first
SQL> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Pr
oduction
With the Partitioning, OLAP and Data Mining options

But when i Checked in EM, ora10grc is shutdown only. Then i tried*

C:\Documents and Settings\MaverickBull>set oracle_sid=ora10grc;

C:\Documents and Settings\MaverickBull>sqlplus sys as sysdba/oracle123@ora10grc

SQL*Plus: Release 10.2.0.1.0 - Production on Fri Nov 19 13:15:00 2010

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Enter password:
ERROR:
ORA-12560: TNS:protocol adapter error

I am getting this error+
I tried from EM & successfully opened.*

Current Status shutdown
Operation startup database in open mode
Initialization Parameter default
Are you sure you want to perform this operation?

-----------------------------------------

When i checked my TNS its showing both in same port.!!. My TNS looks like this.

ORA10GRC =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = renji)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = ora10grc)
)
)

ORA10G =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = renji)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = ora10g)
)
)

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
)
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
)
)



Please Help How can i manage both database from the cli. I mean switch between database, shutdown,startup both the database etc. Also at one point of time, how can i check which database i am working with.(say for example, i forget which ORACLE_SID i set)

Thanks
Ranjith